Cadillac 1994 Seville Owners Literature page 82

Power Door Locks
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Rear Door Security Lock
Your Cadillac is equipped with rear door security locks that help prevent
passengers from opening the rear doors of your car from the inside. To
use this lock,
1. Move the lever on the door all the way up to the ENGAGED position.
2. Close the door.
3. Do the same thing to the other rear door lock.